System of control



SYSTEM OF CONTROL Filed June 1, 1951 Fig. l.

Fig.2. v Fig.3. Fig.4. Fig.5. Inventor! I 24 34 [r 1 Robetb B. Taylor,

' y Low [1-55 fl-s5 5- 5 [1- His Attorney Patented May 23, 1933 *UNITED STATESPATENT oFFicE ROBERT B. TAYLOR, F

SCOTTA, NEW'YORK, ASSTGNOB '10 GENERAL ELECTRIC COM- PANY, A COBCE'ORATIQN OF NEW YORK SYSTEM OF GONTRQL described and claimed in a copending application of Walter O.'Lum, Serial No. 295,059, filed July 24, 1928, assigned to the same assignee as this invention and of which my invention is an improvement. The invention of the aid Lum application was made prior to my invention and I, therefore, do not herein claim anything shown or described in Lum application which is to be regarded as prior art with respect to this present application. 7

In carrying out my invention in one form I provide a manually operated switch in the elevator for controlling the starting of the elevator and its deceleration to a predetermined low speed, such as 150 it. a minute, after which the elevator is brought to the floor and leveled automatically under the control of the electric discharge devices. I further provide two electric discharge devices mounted in vertically spaced relation on the elevator and a pair of control vanes mounted in the hatchway at each floor and spaced apart a distance corresponding to the spacing of electric discharge devices. In the operation of this leveling equipment the two electric discharge devices are each provided with a pa r of control windings, the inductive relation of which is controlled by the vanes which pass between them as the elevator moves up and down. pair controls the leveling in the up direction while the upper vanecontrols the leveling in the 'down direction. As the elevator a proaches the floor at which a stop is to cc to control systems for said The lower vane o'lt each Application filed June 1, 1931. Serial No. 541,237.

made, the electric discharge devices come successively into cooperative relation with the nearest vane and successively pass out of cooperative relation with it into the space between the vanes so that the speed of the elevator is reduced in a plurality of steps. .When the electric discharge devices arrive in the space between the vanes so that there is no longer any cooperative relation between them and the vanes, the elevator will have been deeelerated to a very low speed. The brake is then automatically applied and the elevator brought to rest leveled with thefloor.

My invenion provides a very accurate and reliable control and makes possible the deceleration of the elevator in the shortest time possible without discomfort to the passengers as well as dependable leveling to within a small floor.

For a more complete undertanding of my invent-ion reference should be hadlto the accompanying drawing in which'Fig. 1 is a diagrammatic representation of a system of elevator control embodying my invention while Figs. 2 to 5 inclusive are diagrammatic views showing details of operation.

Referring to the drawing, in the specific embodiment shown the elevator car is raised and lowered by a main driving motor 11 which is connected thereto in any suitable manner. For purposes of illustration the motor is shown connected to a winding drum 12 for the elevator cable. This driving motor is connected in a Ward- Leonard sys tem with'a generator 13 which is driven at a substantially constant speed by means of a suitable driving motor (not shown). The

fraction of an inch above or below the motor and generator are connected together ing 17 in order to properly input or grid and output or by means of reversing switches 20 and 21 operated respectively by the coils 22 and 23.

Various control devices are provided for controlling the energization of the field windaccelerate the elevator, todecelerate it and to level it at the floor. It is believed that a clear understanding of the arrangement and operation of the various parts of the system will be best un- 10 derstood from a complete description of the operation of the system as a whole and therefore the construction and arrangement of certain of the devices only will be first described in detail. i

Special attention is directed to the arrangement of the electric discharge device control. As shown, two electric discharge devices 24 and 25 of the three-element type are provided. These devices are'mounted on the elevator 10 by meansof suitable brackets in some such relative position as indicated, the

device 24 being uppermost. Brieflystated, these electric discharge devices are each proyided with a pair of electrical coils in their plate circuits, respectively, which coils are so mounted as to be in mutual inductivev relation with each other, although spaced apart somewhat, and thereby maintain the discharge devices in an oscillating condition. Under these conditions the relay coils 26 and 27 in their output circuits respectively are in effect deenergized,

the radio frequency oscillating current being then bypassed around the coils through the condensers 28 and 29, and the direct current through the coils being of a low value as compared to the current required to operate them.

As shown, the discharge device 24 is rovided with inductively related spaced coi s 30 and 31 in its grid and plate circuits respectively while the discharge device 25 is provided with corresponding coils 32 and 33. The coils are so mounted on the car that the center lines or axes of the coils of each pair are coincident and at right angles with the length of the hatchway.

Mounted in the hatchway adjacent each floor are a pair of spaced vanes 34 and 35.

' These vanes are mounted in alinement one above the other throughout the length of the hatchway and in such lateral position that they pass between the pairs of coils carried by the elevator car as it moves in the hatch way. The vanes are made of a suitable elecmaterial such as iron or magnetic shield to electromagnetically isolate the two coils of tween them; In a typical installation the vanes were made of sheet iron having a thickness suflicient to give the necessasry mechanical strength, about ,4,", while the coils of 7 each pair were spaced apart about 1", to give suflicient clearance on each side of the vane to allow for lateral clearance of the elevator each pair when it comes be-.

car on its tracks. When a vane comes between a pair of coils as the elevator moves in lating condition in the discharge device is terminated. Under these conditions a direct current flows in the output circuit of the particular discharge device and energizes the relay coil 26 or 27 as the case may be. The motor 11' is provided with a field winding 37 which is connected to the supply mains 18 and 19 by means of the conductors 38 and 39.

The two vanes at each floor are spaced apart vertically a distance corresponding with the vertical spacing of the electric discharge devices or more specifically the vertical spacing of the two pairs of coils associated with the electric discharge devices on the car. This spacing is such that a zone is provided between the vanes for the two pairs of coils in whichzone neither vane has anv cooperatii'e relation with the pairs of coils. It is in this position that the elevator brought to rest. This position is well defined so that movement of the elevator a fraction of an inch in either direct-ion affects the oscillating condition of one of the discharge devices and thereby causes the driving motor be automatically started and the elevator brought back to the floor. It will. of course, be understood that while the. pairs of vanes and the pairs of discharge devices are not aetually located at the landing floor levels. they are situated equal distances from the floor level such that when the stopping conditions, previouslv mentioned. are complied with the elevator is leveled. As shown. the pair of vanes at each floor is mounted at such distance above the floor that a point midway between the vanes is the same distance above the floor that a point midway between two pairs of discharge device coils on the elevator car is above the floor of the car.

Ordinarily where the elevator does not overrun the floor only one of the vanes is utilized in leveling, that is, the vane that is, first reached, as the pair of coils come successivel y into cooperative relation with this vane and move successively out of cooperative relation with that vane into the space between lng in a downward direction. Fig. 5 shows the two pairs of coils midway between the two vanes under WlllCll condition the elevator is leveled at the floor and has been finally brought to rest by the application of a suitable brake.

T It is now believed that a comprehensive understanding of the invention, including the construction and arrangement of the Va rious apparatus as well as its operation, will be facilitated by a description of the operation of the system as a Whole.

Assuming that the elevator is to be started in a downward direction, the manuallyoperated control or car switch 40 is thrown from its central off position shown toward the left as viewed in the drawing into engagement with the first cooperating stationary contact 41. It will be understood that this movable car switch member comprises a pivotally mounted, arcuate, electrically conducting member which is electrically connected to the supply main 18 through a conductor 42. \Vhen moved toward the left this arcuate contact member successively engages three stationary contacts 41, 43 and 44, while when moved from the central position shown towards the right it/successively engages the three contacts 45, 46 and 47 in the order mentioned. \Vhen the contact 41 is engaged a circuit is established from the supply main 18 through the conductor 42, the movable switch member, conductor 48, a relay switch 49 actuated by the reversing switch 20 and closed as shown when the switch 20 is open, then through the coil 23 for the switch 21, conductor 50, the relay operating coil 51 and con- 7 ductor 52 to the supply main 19. This energizes the two operating coils 23 and 51 in series across the supply main whereby the reversing switch 21 is pulled upward to the closed position at the same time opening the relay switch 53 and closing the relay switches 54 and 55 actuated thereby.

The energization of the coil 51 closes the relay switch 56 which closes the circuit for the brake. coil 57 whereby the brake is released against the force of a spring tending to apply it. This circuit leads from the supply main 18 through the conductor 38, the switch 56, the coil 57 and the conductor 52 to the supply main 19. The closing of the switch 21 closes the circuit for the generator field 17 in a direction to cause the motor 12 to drive the elevator in a downward direction. This circuit leads fromthe supply main 18 through the two resistances 60 and 61 in parallel with each other, the switch 62' then being deenergized and closed in accordance with its bias thence through the conductor 63, the upper switch member of the switch 21, conductor 64-, field 17. conductor 65, the lower switch mem ber of the switch 21, and conductor-66 to the supply main 19.

It should be noted that the switch 62 is now closed by reason of the fact that when the car switch is thrown from its central position shown in either direction to an operating position a switch arm 70 mechanically and electrically connected thereto is moved to an open circuit position whereby the circuit of the opcrating coil-71 of the switch 62 is opened. The switch 62 thereupon closes immediately in accordance with its bias. This circuit for the coil 71 may be traced from the supply main 18 through the conductor 42, switch 70, conductor 72, a switch 73, conductor 74, a

switch 7 5 which is then closed, conductor 76, switches 77 or 78, or both, both of which are now closed, conductor 79, coil 71 and conductor 80 to the supply main 19. The switches 77 and 78 are closed byreason of the fact that the discharge devices 24 and 25 have their output circuit opened also by the switch 70 and consequently, the'coils 26 and 27 in their output circuits are deenergized I so that the relay switches 81 and 82 actuated thereby are closed in accordance with their biases. Circuits are thereby established for the coils 83 and 84 whereby the switches 77 and 7 8 are closed. The circuits for the coils 83 and 84 may be traced from the supply main 18 through the conductor 85, the switches 81 and 82 and coils 83 and 84 in parallel and thence through the conductor 86 to the supply main 19.

As previously stated, the switch 70 is also in the output circuit for the electric discharge devices, This output circuit leads from the positive supply main 18 through the conductor 42, the switch 70. the conductor 72, switch 73, conductor 87, to the coils 26 and 27. From this point the output circuit for the discharge device 24 leads through the coil 26. the conductor 88, the coil 31 of the discharge device 24 and thence through the discharge device from the anode 90 to the cathode 91 to the conductor 92 and then through the cathode 93 of the discharge device 25 and the conductor 94 to 'thesupply' main 19. From the c011- ductor 87 the output circuit for the discharge device 25 leads through the coil 27, conductor 89, coil 33 to the anode 95 and from the anode 95 of that discharge device to its cathode 93 and thence by the conductor 94 to the supply main 19. It should be noted here that for heating purposes the two cathodes 91 and 93 are connected in series with each other and with a resistance 96 across the supply source,

the resistance 96 serving to limit the heating current for the cathodes to a desired value. This circuit leads from the supply main 18 through the conductor 97, resistance 96 and the two cathodes and conductor 94to the supply ina-in 19. The voltage drop across the resistance 96 also provides the potential necessary for the output circuits of the-discharge devices. As long" as the car switch is in a .running position, therefore, the switch 70 maintains the output circuits of the discharge devices open and consequently the elevator runs past the leveling vanes 34 and 35 at each floor without being influenced by them.

. Continuing with the operation. with the two resistances 60 and 61 in parallel with each other in its field circuit, the generator now v the elevator has a weak field and generates sutficient volt-.

age to start the driving motor 11 and accelerate the elevator to a relatively low speed. As comes up to this low speed the operator throws the. switch 40 over to the next point making contact with the contact 43 whereby a circuit'is closed for the operating coil 100, this circuit leadingfrom the supply main 18 through the conductor 42, switch 40, conductof 101, coil 100 and conductor 80 to the supply main 19. The coil 101 closes .the switches 102, 103, 104 and opens the switch 75. The closing of the switch 104 connects the resistance 105 in parallel with the resistances 60 and 61 whereby the generator field is increased and the elevator thereby accelc rated to a higher speed.

vA holding circuit for the coils 23 and51 is established by the switch 103, this circuit leading from the supply main 18 through the switch 103, theconductor 106, theswit-ch 54 which is now closed, the conductor 107, conductor 48 thencedthrough the relay switch 49 through the coil 23, etc., to the supply main 19. This holding circuit, it will be observed,"

is in parallel with the car switch 40 and its purpose is to take the deceleration of the eleyator away from the control of the car switch whi ch, it will be observed, can now be thrown to the off position at any time without imniediatcly dcenergi-zing the generator field 17.

The closing of the switch 102 forms a holding circuit for coil 100 to enable switch 103 to remain closed as required for the holdmg circuit described in the previous paragraph. This holding circuit is from supply main 18 through switch 102, conductor 108,

switch 55, conductor 109, switch 110 actuated by the coil 83 and now, closed since the coil is energized, conductor 111, coil 100, and conductor 80 to supply main 19. The opening of switch 75 at this time has no immediate effect, this switch being utilized later on durilig the deceleration of the elevator.

In continuing the acceleration of the elevator, the operator throws the car switch farther to the left into engagement with the contact 44. This completes-a circuit for the op erating coil 112 which closes the switch, 113 thereby establishing a short circuit through the conductor 114 for the three resistances 60, 61 and 105. This connects the generator field directly across the supply main and gives the highest elevator speed. The circuit for the coil 112 may be traced as follows: from the conductor 18 through the conductor 42 to the car switch, conductor 115, the coil 112 and conductor 80 to the supply main 19. After a certain interval necessary for ac- .celeration, the car will now come up to its full'runmng speed.

tion of the discharge devices by the first set i of vanes reached when the car switch is centered more than one fioors distance away from the stop. It is opened by a coil 116 which is connected across the armature of the main driving motor 11.. This coil is so designed that it holds the switch 73 open untilthe voltage across the motor 11 has decreased to a value corresponding to a. low value of elevator speed at which time the elevator will be fairly close, few feet of the desired landing. As shown the switch 73 is in the output circuit of the discharge .devices.

Assuming now that the car switch is centered for a stop, this immediately opens the circuit for the coil 112 whereby the switch 113 opens, connecting the three resistors 60,

61 and 105 in parallel with each other in circuit with the generator field 17. The switch 62 is now closed since the circuit of its coil 71 is open at two points represented by the switches 73 and 75 which are both open. At this time the coils 23 and 51 are maintained energized by the holding circuit through the switch 103, and the coil 100 is likewise energized by a holding circuit through the switches 102 and 110. This decelerates the elevator to some low speed such as 160 or 170 feet a minute. The centering of the car switch also closes the switch 70 mechanically connected therewith which partially completes the output circuit for the electric discharge devices as well as partially completing the circuit for the coil 71. The next step as the elevator slows down is the closing of the switch 73 due to the decrease in the voltage across the driving motor 11. The dis charge devices are now energized ready to complete the deceleration and stopping of the elevator automatically when the next pair of vanes is reached.

When the elevator has decelerated or nearly decelerated to the low speed of about 160 to 170 ft. a minute, the electric discharge v grammatically in Fig.

42, switch the switches 102, 103 and 104 drop open the supply main 18 through the conductor 70, conductor 72, switch 73, conthe coil 27, coil 33 through the device from its plate 95 to its 94 to the ductor 87, discharge filamentary cathode 93, conductor supply main 19. a The energization of the coil 27, however, has no immediate effect upon the control, the opening of the switch 82 serving simply to deenergize the coil 84 which allows the switches 7 8 and 122 to open.

In the next step the discharge device 24 comes under the influence of the vane 34 whereby the coil 26 is energized and operates to open its lower switch 81 and close its upper switch 121. This position of the discharge devices and vanes is indicated dia- 3. The opening of the switch 81 deenergizes the coil 83 whereby the switches 7 7 and 110 are opened. The switch 110 opens the circuitfor the coil 100 whereby and the the switch 75 closes. The opening of J switch 104 takes out the parallel resistance section 105 leaving the resistances60 and 61 in parallel, thus increasing the resistance in the generator field whereby the elevator is decelerated to some lower speedftor example, ft. a minute. I V l The closing ofthe switch-121 established a holding circuit for the operating coils 23 and 51 in parallel with the switch 103 sothat the opening of the switch 103 does not deenergize the coil 23. This holding circuit may be traced from the supply main 18 through the conductor 85, the switch 121 to the conductor 48 and thence through the switch 49, the coils 23 and 51 and the conductor 52 to the supply main 19.

As the elevator continues, the discharge device'25 leaves the lower end of the vane 34, as indicated in Fig. 4, whereupon its oscillatory condition is resumed and the coil 27 is deenergized. The switclf 82 is thereby closed whereby the coil 84 is energized. his closes the switches 78 and 122, the switch 78 establishinga circuit for the coil 71, since the switches 73 and 7 5'are now both closed,

5 which 'is thereby energized and opens the switch 62 thus leaving only the resistance in series with the generator field. The generator field "current is thereby still further reduced and the elevator decelerated to a low 1 been traced.

of about 22 ft. the coil 71.has

leveling speed, forexample, a minute. The circuit for IWhen the elevator has decelerated or nearly so to the low leveling speed of perhaps 22 ft. a minute it will be quite close to the landing, perhaps 1" from the landing. At this time the discharge devicd 24 leaves the influence of the vane 34, the two discharge devices then lying in the space between the .vanes as indicated diagrammatically in- 5. This deenergizes the coil 26 and the swit 121 thereupon opens in accordance with its bias, opening the holding circuit for the coil 23 whereby the coil 23 is deenergized and also the coil 51 in series with it. The main switch 21 thereupon drops out deenergizing the generator field and the switch 56 opens thereby opening the circuit ofthe brake coil 57. The brake is thereupon applied in accordance with its spring bias bringing the elevator to rest at the landing.

It will be understood that, if necessary, suitable means not shown will be provided for reducing the residual magnetism of the generator which might in some cases result in the car creeping even when the brake is applied. Suitable means not shown may also be provided for so controlling the acceleration so that the car switch may be drawn directly to the such as a flywheel generator for controlling the generator field, as described and claimed inja copending application of Max A. W'hiting, Serial No. 422,460, filed J an. 21, 1930.

In case the elevator overruns the landing in the downward direction the coil 27 is energized and ,theswitch 120 thereby closed to establish a circuit for the up contactor coil 22 whereby the switch 20-is closed and the generator field energized in the opposite directionto bring the elevator back, the resistor 60only being in the circuit. Since the coil 100 is now deenergized the switch 104 is open; The coil 71 is energized at this time through the switches 75 and 7 8 whereby the switch 62 is maintained open. This returns the elevator at the low leveling speed of about 22 it. a minute.- When the discharge device 25 moves out of the influence of the lower vane 35 the coil 27 is deenergized whereby the circuit of the coils 22 and 51 is broken and the brake applied. The circuit for the coil 22 'established .by the switch 120 maybe traced as follows: From the supply conductor 18 through the conductor 85, switch 120, conductor 123, switch 53 which is closed when the coil 23 is deenergized, coil 22, conductor 50, coil 51*i1nd conductor 52 to conductor 19.

In case the elevator overruns far enough for the discharge device 24 to operate, the coil 26 is energized which opens the switch 81 and as a result causes the switch 77 to openand deenergize coil 71. Switch 62 thereupon closes so that the releveling is accomplished in part at-a higher speed. I

It is believed that the operation of the system in the upward direction of travel. for the elevator will be clearly understood from the foregoing description of the operation in the downward direction and consequently the operation in the upward direction will not be traced in detail. It will be sufiicient to say that the control of the resistances 60, 61 and 105 to accelerate and decelerate the elevator is the same as previously described in confull sped position in starting,

the supply main obJeCt. V

nection with the down direction, the difference being that the functions of the discharge devices 24 and 25 are reversed. For the upward direction the car switch .is, of course, thrown from the center position toward the right.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit-andscope ofm invention.

at I claim as new and desire to secure by Letters Patent of the United States, is:

1. Means for controlling an object movable in a constrained path comprising a pair of control devices mounted in spaced relation to each other in the direction of said path, a pair of control devices mounted on said obJect in spaced relation to each other in the direction of said path in position to each cooperate successively with each of said first devices during the movement of said object, andmeans responsive to the relative positions of said pairs of devices for controlling the direction of movement and position of said 2. Means for controlling an object movable in a constrained path comprising a pair of control devices mounted in spaced relation to each other in said path, a pair, of control devices mounted in spaced relation on said object in position to each cooperate successive-1 1y with each of said first devices during the movement of said object, the devices of said pairs bein widely and narrowly spaced apart so t at the spaced pair is greater than the overall spac} ing of said narrowly spaced pair, and means responsive to the successive cooperation of said devices for controlling the movements of said object so as to bring said object to rest with said narrowly spaced. pair of devices in the-space between the devices of the other pair.

3. In an electric elevator or the'like, the combination with a hatchway, a car in said hatchway and leveling means for governing the travel ofsaid car in Saidhatchw'ay, saidleveling means comprising a pair of devices mounted in said hatchway in spaced relation with each other and a pair of devices mounted on said car in spaced relation with each other arranged to each cooperate successively with each of said first pair of devices durmg the movement of said car in said hatch- Way and means responsive to the relative positions of said pairs of devices for controlling the direction of movement and position of said car. .4. A control system, for electric elevators and the like comprising the combination with a hatchway, a car in sald hatchway and levelspacing 'of' said widely ing means for governing the travel of said car in said hatchway, said leveling means comprising two pairs of devices respectively spaced widely and closely apart mounted respectively on said car and in said hatchway, the devices of each of said pairs being arranged to cooperate with the devices of the other pair during the movement of the car in the hatchway and means responsive to the relativepositior'i's of said pairs of devicesfor controlling the speed and direction of movement of said car so that the car is brought to rest with said narrowly spaced pair of devices between said widely spaced pair of devices. p

5. A system of control for an object movable in a constrained path, comprising driving means for the object, a pair of spaced inductive devices mounted on the object, a pair of metallic spaced vanes mounted in said pathway so as to vary the inductive characteristics of said inductive devices during the movement of the ob eCt, control means for said driving means responsive to said change in the inductive characteristics of said devices to decelerate said object in steps in response. to the successive cooperation of said inductive devices with said vanes during movement of the' object and thereby bring the object to rest with said inductive devices between said yanes. U

6. A control system for an object movable in a constrained path comprising driving means for the object, metallic vanes mounted in said path, a pair of electric discharge devices mounted in spaced relation with each other on said object, control means for said discharge devicescooperating with said vanes during the movement of the object and control means for said driving means operated by said discharge devices during the'success'ive cooperation of said discharge device control means with said vanes.

7. A control system for an object movable in spaced relation with each other on said object, controlmeans for said discharge devices cooperating with said vanes during the movement of said object, control means for said driving means operated by said discharge devices during the successive cooper-- .ation of said dischargedevice control means with said vanes so as to bring the object to rest with the discharge device control means between said vanes.

8. In a system of elevator control the combination with a hatchway and a car movable in the hatchway of a pair of vanes mounted A in the hatchway in spaced relation with each other, a pair of electric discharge devices mounted on said car in spaced relation with each other provided with control means in of electric driving means in the hatchway in spaced relation with each other, a pair of electric discharge devices mounted on said car in spaced relation with each other provided with control means in position to move into cooperative relation with said vanes during the movement of the car in the hatchway, means for controlling the deceleration of said car in steps, and means responsive to thesuccessive cooperas tion of said discharge devices with the first vane in the path of said car to successively operate said control means to effect the decol- 5 eration of said car in said steps.

10. A control system for elevators and the like comprising the combination with a hatclrway and a car movable in the hatchway for the car, reversing switches for controlling said driving means for forward and reverse operation, resistances in a circuit of said driving means for controlling the acceleration and decelera-. tion of said car, electromagnetically opersaid hatchway in position atcd control switches for controlling said resistances, a manually operated carswitch for controlling said reversing and control switches to start and accelerate said car, a pair of electric discharge devices each provided with input and output circuits mounted onisaid car in spaced relation with each other, controlmeans for said discharge devices, a pair of metallic vanes mounted 1n said discharge device control means during the movement of said car in the hatchway and thereby control said output circuits, and means included in said output circuit for operating said control switches to control said resistances irusteps as the discharge devices successively come into' cooperative relation with thefirst of said vanes in their path and ation of said car,

, like comprisin thereby control the deceleration of said car.

11. A control system for elevators and the g the combination with a hatchway and a care movable in the hatchway of electric driving means for the car, reversing switches for controlling said driving means for forward and reverse operation, resistancesin' a circuit of said driving means for controlling the acceleration and decelerelectromagnetically operated control switches for controlling said resistances, a manually operated car switch to cooperate with "for controlling said reversing and control switches to start and accelerate said car, a pair of electric discharge devices each provided with input and output circuits mounted on said car in spaced relation with each other, control means for said electric discharge devices, a pair of metallic vanes mounted in said hatchway in position to cooperate with said discharge device control means during the movement of said car in the hatchway and thereby control said output circuits, said vanes being spaced apart more widely than said discharge devices, means responsive to the position of said car switch for controlling said output circuits,

means included in said output circuits for operating said control switches to control said resistances in steps as said discharge devices successively move by the first of said vanes in their path, a brake for said car, and means included in said output circuits for applying said brake to stop said car when said discharge device control means move into a position between said vanes.

l2. A control system for elevators and the like comprising the combination with a hatchway and a car movable in said hatchway, electric driving means for said car, reversing switches for controlling said driving means forforward and reverse operation, resistances in a circuit with said driving means for controlling the acceleration and deceleration of said drivingmeans, electromagnetically operated control switches for controlling said resistances. a manually operated car switch for controlling said reversing and control switches to start and accelerate said car, a pair of electric discharge devices each provided with input and output'circuits mounted on said car in spaced relation with each other, control means for saiddischarge devices, a pair or metallic vanes mounted in said hatchway in position to successively move into cooperative relation with said discharge device control means during the movement of said ear in the hatchway and thereby control said output circuits, means included in said output circuits for operating said control switches to control said resistances in steps, means for inserting a resistance in said circuit the second electric discharge device reaches the first vane in its path, means for inserting an increased resistance in said circuit when the first discharge device leaves said vanes, a bralze'for said car and means for applying said bnke when the second discharge device leaves the first vane.

1-8. Meansfor controllingan object movable in a constrained path, comprising driving means for the object, an inductive con trol device carried by the object, a pair of members mounted in spaced relation and in alinement in the direction of said path arranged to each cooperate with said inductive when device to vary the inductance of said device during the movement of said object, means responsive to the cooperation of said inductive control device with the first of said members in its path for controlling said motor to decelerate said object so as to bring it to a stop with said inductive control device between said pair of members, and means responsive to cooperation of said inductive 10 control device with the other of said members in case the object overruns to reverse the object and stop it with said inductive control device between said pair of members. In Witness whereof, I have hereunto set my hand.

ROBERT B. TAYLOR. 

